IMAGING CORE ? CORE C: PROJECT SUMMARY/ABSTRACT The BIOCARD study is a longitudinal, observational study of 349 individuals who were cognitively normal and primarily middle aged (mean age=57.1) at enrollment. The subjects have now been followed for up to 27 years. The overall objectives of the project are to further advance the study of preclinical Alzheimer?s disease by: (1) clarifying the pattern and rate of change in AD biomarkers (including those based on CSF, blood, MRI, and PET imaging) and cognition; the biomarkers to be studied include several promising novel biomarkers derived from blood, CSF and brain imaging. (2) maximizing our data by working collaboratively with several research groups who have comparable data, and (3) providing a publicly accessible data, brain scans, and biological specimens, for researchers in the field. To accomplish these goals we established 7 Cores and, with this application, are also including 2 projects. The Imaging Core (Core C) is responsible for overseeing the acquisition and analysis of magnetic resonance imaging (MRI) scans and positron emission tomography (PET) scans in the BIOCARD study participants. The specific aims include: (1) to facilitate the continued acquisition of 3T MRI scans in the participants, (2) to facilitate the continued longitudinal acquisition of PET scans, using Pittsburgh Compound B (PiB), and the initiation of Tau PET imaging, using MK6240, (3) to integrate the 1.5T volumetric data collected at the NIH with the 3T MRI volumetric data collected at Johns Hopkins, (4) to integrate the MRI and PET imaging data with the clinical, cognitive, CSF and blood biomarker data generated by Cores B and D and Project 1, (5) to examine the order and timing of MRI and PET biomarker changes during preclinical Alzheimer?s disease, (6) to integrate high field MRI images of brain tissue with detailed neuropathological findings in the same individuals, and (7) to continue to share image files and related clinical information with investigators in the field.